Forensic Anthropology What We Learn From Bones Miss Jones 2015

BONE BASICS

The Human Skeleton Adults Have 206 Bones Babies Have 450 Bones Bones fuse as we develop Axial Skeleton Skull, vertebral column, and rib cage Appendicular Skeleton Pelvis, arms, legs, ect…

Major Bones of Body KNOW BONES ON DIAGRAM Sacrum Name, location, spelling Sacrum At end of vertebral column Coccyx at end = tail bone Pelvis = Ileum Ishium Pubis (pubic bones)

Development of Bone Osteoblast cells (osteocytes)—specialize cells where bones originate. Skeleton starts out as cartilage Ossification—osteoblast cells (osteocytes) migrate to the center of cartilage areas and deposit minerals such as CALCIUM PHOSHATE that give bone strength and rigidity. Starts to turn to bone after a few weeks of in utero development At 8 weeks a skeleton is visible with x-ray Process continues throughout lifetime. Life Cycle of Bone- bone is deposited, breaks down, and is replaced Osteoclasts—the 2nd type of bone cell, specialized to dissolve bone Osteoblasts – replace bone that is destroyed by osteoclasts

Interesting Fact The skeleton has completely replaced itself every 10 yrs

COMPARE AND CONTRAST Osteoblasts (osteocytes) and Osteoclasts

Structure of Long Bones Periosteum Protective membrane or covering Contains blood vessels and nerves keeps bones moist Aids in recovery from injury Epiphysis- the ends of the bone Epipyseal (growth) plates located here Cartilaginous areas Close during stages of life a filled with bone Diaphysis- the shaft or long middle portion of bone Spongy Bone NOT ACTUALLY SPONGY More porous, located in/on epiphysis Compact Bone Stronger bone of diaphysis Contains cavity Medullary cavity Contains bone marrow Where blood cells are produced

RECALL AND SHARE PERIOSTEUM EPIPHYSIS DIAPHYSIS SPONGY BONE COMPACT BONE MEDULLARY CAVITY

What Protects the Ends of Bones? Articular cartilage—wraps the ends of bones for protection and prevents scraping Think chicken wing Does not regenerate Age Injury

What Connects Bones? ligaments—bands of connective tissues that connect two or more bones together

How Do Bones Move? Muscles attach to Bones to cause movement tendons—connect muscle to bone

Time to Process Describe the role of cartilage (articular), ligaments, and tendons in the skeletal system

Forensic Anthropology Studies the identifying characteristics of the remains of an individual SKELETON So what can a skeleton tells us? Sex Height Race/Ethnicity Physical Health and/or History of Disease Identification Dental Records Mitochondrial DNA What Happened?

Distinguishing Males From Females OVERALL SKELETON Female Skeleton Smoother Less “knobby” Male Skeleton Thicker Rougher Quite Bumpy (why?) Male hormones = more muscle development Surface of bone where tendons attach is thicker

Sex Determination SKULL Male Characteristics Trait Female Characteristics More square Shape of eye More rounded Mandible shape from underside More V-shaped Thick and larger Upper brow ridge Thin and smaller

Sex Determination SKULL Male Characteristics Trait Female Characteristics Present Occipital protuberance Absent Low and sloping Frontal bone Higher and more rounded Rough and bumpy Surface of skull Smooth Straight Ramus of mandible Slanting Nuchal crest

Sex Determination SKULL Is the female skull smoother than the male’s? Which frontal bone is lower and sloping? Are the male’s eye orbits more circular? Which jaw is more square, with an angle that is closer to 90o?

Sex Determination PELVIS An easy method to determine gender The surface of a woman’s pelvis can be scarred from pregnancy/child bearing The sub pubic angle of the female pelvis is greater than 90o; the male’s, less Pelvic cavity Male heart shape, usually sacrum and coccyx visible Female oval, usually only coccyx visible

Sex Determination FEMUR The male femur is thicker and joins the pelvis at a straighter angle than the female femur

Age Determination SKULL LAMBOIDAL SUTURE Begins closing at age 21 Accelerates at age 26 Closed age 30 SAGITAL SUTURE Closes by about age 32 CORONAL SUTURE Closed at about age 50

Age Determination LONG BONES At birth—450+ bones in the skeleton Adults— 206 bones Epiphysis line—appears where cartilage is replaced by bone When the cartilage is fully replaced, the line is no longer visible This information can be used to approximate a skeleton’s age

Height Determination Measurements of LONG BONES like the humerus and femur can be used to calculate a persons height Involves calculations Example 2.10 x (length of femur in cm) + 72.22 cm = height of person in cm. + or – 3.91 cm (about an 1 ½ inches)

Race Determination Race can be very hard to determine. WHY? Shape of eye orbits Caucasoid = rounded, somewhat square Negroid = rectangular Mongoloid = rounded, somewhat circular Nasal Spine Caucasoid = prominent spine Negroid = very small spine Mongoloid = somewhat prominent spine Nasal Index Caucasoid = <.48 Negroid = >.53 Mongoloid = .48-.53 Prognathism Caucasoid = straight Negroid = prognathic Mongoloid = variable Femur Caucasoid = fingers fit under curvature Negroid = fingers do not fit under curvature Mongoloid = fingers fit under curvature

Identification Dental records Height Right vs Left Handed Facial Reconstruction

DNA and Identification Bone contains little nuclear DNA but it does contain mitochondrial DNA Nuclear DNA degenerates before mitochondrial DNA Mitochondrial DNA is inherited only from the mother Compare results with living relatives on the mother’s side of the family

Right vs Left Handed Bones are usually more developed on the side that is used most why? Sometimes there may also be more deterioration.

History of Disease / Prior Surgeries Scoliosis Osteoporosis Arthritis Surgeries Rods, plates ect.. Have id number

Skeletal Trauma / Cause of Death Sharp Force Weapons, Blunt Force Trauma, Gunshots All make distinct fracture patterns Blunt force generally more widespread fractures and greater damage to bone than sharp objects